>So presumably when the control records were created, CA software did a NOTE of >the TTR of the beginning of each >volser range and saved the results of the >NOTE in the control record. This saved NOTE value was the base to which >the >offset, calculated from the user's input, was added. > >Bill Fairchild >Programmer >Rocket Software >408 Chamberlain Park Lane • Franklin, TN 37069-2526 • USA >t: +1.617.614.4503 • e: [email protected] • w: >www.rocketsoftware.com
It's actually a relative block number, not a TTR. The TMS TMC file was originally fixed length 256 byte records that were unblocked. The first several records contained control information, (like volser ranges and relative block numbers), and other stuff, (like the relative block number for the start of the DSNB records). Let's say there were 3 control records in the TMC. That would mean the record for volser 000001 would be the fourth record/block so the relative block offset would be 3. Volser 000010 would be record/block 10 plus offset 3 so the volser record would be in the record/block 13, which would then be converted into a TTR value based on how many 256 byte blocks there are in a track. Years later, TMS was enhanced to support having the TMC file blocked so now you had to compute the offset into the block to get the correct volser record after reading the correct block. -- Dale R. Smith ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
